This invention relates to ion feedback electron multiplier devices; and particularly to such devices employing input electron optics for the electron multiplier.
Cathodoluminescent display devices, such as for television, have been suggested wherein the electrons are supplied by a multi-dynode electron multiplier operated in a sustained ion feedback mode. These devices have a cathode, as a source of electrons for the multiplier, which emits secondary electrons upon bombardment by ions. If such devices employ a separate electron multiplier for each elememt in a line of the picture, conventional electron multiplier geometry becomes impractical in the physical confines of a display device. The flexibility of positioning the multiplier dynodes with respect to the cathode is severely restricted in such devices.
As a solution to these design restrictions, so called flat multiplier structures have been proposed. These structures employ planar dynodes positioned in two staggered parallel groups. At one end of the multiplier is the cathode which is perpendicular to the planes of the dynode groups. However, this perpendicular structure with planar dynodes, does not provide the high level of electron transmission from the cathode to the first dynode which is necessary for effective operation of the feedback multiplier.